


Sweet Thing

by funnierinpylean



Category: Captain America (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Angst, De-Aged Steve Rogers, Jealousy, M/M, Non-Serum Steve Rogers/Winter Soldier Bucky Barnes | Shrinkyclinks, Not Canon Compliant, Older Man/Younger Man, Pre-Serum Steve Rogers, Protective Bucky Barnes, Time Travel, slow-burn
Language: English
Status: In-Progress
Published: 2020-11-30
Updated: 2020-11-30
Packaged: 2021-03-09 22:48:39
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,120
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27794107
Author URL: https://archiveofourown.org/users/funnierinpylean/pseuds/funnierinpylean
Summary: “Bucky, why is that man inside a robot?” says Steve, weakly.“Because, we’re in the future, Steve,” says Bucky.Steve faints.***The one where Steve gets de-aged to 17 years old in the middle of a mission, and Bucky has to figure out how to keep his headstrong, now teenaged-husband, safe.
Relationships: James "Bucky" Barnes/Steve Rogers
Comments: 16
Kudos: 145





	Sweet Thing

**Author's Note:**

> This doesn't have any underage in it, but there is explicit sexual activity when Steve turns 18, so, nope out now if that squicks you out. 
> 
> I wanted a de-aged Steve fic that actually takes it seriously, what it would mean to take a younger version of Steve and drop him into the modern Avengers universe, with a Winter Soldier Bucky and all. I wanted more than just a quick "now he's a kid, now he's not" look at de-aging; I wanted de-aging with actual angst, so here we are. 
> 
> Enjoy!
> 
> (This is supposed to take place two years after the end of Endgame, but I kind of "forgot" that Nat and Tony are "dead" as well as the whole old Steve thing. Also, Stark Tower is back!)

“That all you can do?” shouts Tony. “Your spells bounced off Cap’s shield like they were rubber,” he says, laughing. He shoots a bolt of energy from his palm, which the witch easily deflects with a spell. 

Bucky tenses, waiting for an opening. He’s commandeered a nearby office about four stories up, and is crouched in a corner, his rifle squarely aimed at the dark witch. The second Cap gives him the go, he’s going to take his shot. 

“Don’t taunt him, Tony.” says Dr. Strange. “Methuselah is one of the most powerful dark mages known to the nine realms. He won’t take a challenge standing down.” Bucky considers taking his earpiece out — anything would be better than hearing the eternal banter of Strange and Stark on a mission. 

“Tony, on your right,” says Steve, calmly, catching the cars that Methuselah has sent flying through the air, before they crash into the fleeing crowd of pedestrians. “And Dr. Strange is right. Don’t taunt the damn thing.”

Methuselah’s lipless mouth curving upwards at the corners, an eerie facsimile of a smile. “You think that’s all I can do, do you, metal man?” he says, but for the life of him, Bucky can’t see his mouth move. The words echo in his mind, they ricochet around in his brain like ping pong balls. Methuselah throws his arm out, and a power pulse knocks everyone — Bucky included — to the ground. 

When Bucky stands, Methuselah has his arms out, he seems to be muttering an incantation at Steve, who is unconscious, who seems to be floating in the air before Methuselah.

Panic floods Bucky as he realises that Steve seems to be twitching unnaturally, that he seems to almost be  _ deflating _ . 

Without a second thought, Bucky takes the shot. Three bullets straight where Methuselah’s heart should be. Methuselah, wounded, drops his arms, and Steve collapses on the ground, lifeless, unmoving. 

Bucky takes a running jump out of the window, landing on the ground hard, cushioned by his metal shoulder. He leaps up, ignoring his body screaming in pain, unholsters a handgun strapped to his thigh, and walks towards Methuselah, shooting directly at him. The handgun clicks — out of bullets. He reaches for the gun strapped to his back, cocks the gun, starts shooting again. 

“I’ll be back,  _ Soldier _ ,” says Methuselah, and disappears into thin air. Bucky doesn’t have time to wonder if everyone could hear that threat or if it was just transmitted to Bucky telepathically; he sprints to Steve’s prone figure. 

“Steve? Steve!” cries Bucky, and he’s skidding to his knees, coming to a full stop at Steve’s body. 

Natasha is at his six, and she’s checking Steve’s pulse — why is his arm so skinny? — “alive,” she says, and Bucky all but collapses, as he pushes aside Steve’s hair, puts his good hand to his too-small forehead, feels the warmth there. 

“Did Methuselah just de-super Captain America?” asks Tony, who has just landed at Steve’s feet. 

“I don’t know, says Bucky, frantically. He’s rolling up the sleeve of Steve’s uniform, which is suddenly way too big for him, so he can press fingers along Steve’s arteries, so Bucky can feel the blood pumping from Steve’s heart into his extremities, so Bucky can confirm what Natasha said for himself. Bucky feels a pulse, but it’s too faint, too faint for comfort. 

“He looks so,” starts Natasha. 

“Small?” says Tony. “Tiny? Puny, as our green friend might say?”

“Come on, Steve,” wake up,” says Bucky, patting lightly at Steve’s cheeks, and he’s considering initiating CPR, when Steve’s eyes finally open. 

“Bucky?” he says, confusedly. 

Bucky hangs back on his heels, and grins at Steve. “Hey, Stevie, it’s me,”

“Who are all these people?” asks Steve, looking around at Natasha and Tony and Rhodey and Dr. Strange.

“We’re your friends, duh,” says Tony. “A little insulted that you don’t remember, Cap,”

“Shut up, Tony,” says Bucky, firmly. “Steve, what do you remember?” 

Steve screws up his face in concentration. “Uh, math class? I was falling asleep in Mr. Petersen’s trigonometry class, and then I woke up, here.”

Natasha’s eyes widen.

“Am I dreaming?” demands Steve. His nose crinkles in disgust. “Why do you look so old, Buck?” he reaches out and touches Bucky’s face. 

“You’re not dreaming, pal,” says Bucky, and he kisses Steve’s palm, and puts his own hand over Steve’s, kneads it into his rough cheek. 

Steve stands up with difficulty, and the other Avengers gasp. He is about a foot shorter than they’re used to — a hair over five feet — and at least a hundred pounds lighter. His uniform hangs off him, the waist of it somewhere closer to his knees. 

Steve turns to Bucky. 

“Why are they all staring at me like that?” asks Steve, hotly. 

“You’re just a lot smaller than we’re used to, Cap,” says Tony. His mask is deactivated, but he’s still wearing the Ironman suit, and Steve, well, he  _ ogles _ . 

“Bucky, why is that man inside a robot?” says Steve, weakly. 

“Because, we’re in the future, Steve,” says Bucky. 

Steve faints. 

* * *

When Steve wakes up, he’s in the softest bed he’s ever been in. He takes a moment to luxuriate in the feeling, stretch out on the sheets, and sigh, and then he remembers. 

He bolts upright, blinking and staring. He leaps out of bed, only a little surprised to realize he’s naked. He wonders, for a moment, who undressed him, and then he sees clothes folded at the foot of the bed he was just sleeping in. 

He dresses, promptly. The clothes fit him perfectly, although they’re tighter than he’s used to. A pair of blue jeans, a white t-shirt, a flannel to go over them. He looks at himself in the mirror. He looks like a tiny lumberjack. Maybe that’s the style in the future. 

He walks out of the bedroom, into maybe the biggest room he’s ever been in. A beautiful woman with red hair is leaning over a granite kitchen island in one corner, sipping at a coffee cup, and she’s speaking to Bucky, this strange future-Bucky, the one with long hair and impossibly huge muscles. He’s wearing a long sleeved sweater and a leather glove over one hand — only the one hand. 

They stop talking and stare at Steve, who stares back. 

“Uh, hi,” says Steve, uncomfortably. 

“Hi, Steve,” says the woman. “You don’t know who I am, right?”

“No idea, ma’am,” says Steve, sighing. He was already getting sick of explaining himself to these people, but he knew he had only just started. 

“I’m Natasha Romanoff,” she says, lip quirking upward at the affectation. “I’m one of your best friends.”

“I’m friends with a girl?” says Steve, stupidly. 

Bucky laughs, throws his head back and actually roars with laughter. 

“Shut up, Bucky,” says Steve, grumpily. He yawns, and approaches the island. “I want coffee,” he says.

Bucky complies, pouring a cup for Steve out of a futuristic looking metal coffee maker. 

“Lots of milk,” Steve orders. 

“I remember,” says Bucky. 

“Steve liked it black,” says Natasha. “Before.”

“This Steve has acid reflux when he drinks it black,” says Bucky, placing a mug in front of Steve. “Remember, not too much,” he warns Steve. 

“I know, I know,” says Steve. He takes a sip, and sighs in pleasure. “That’s better than anything I’ve ever had in my life,” he says, and takes another large sip. 

“Yeah, coffee sucked during the Depression,” says Bucky, laughter still ringing in his voice. 

“So I take it that’s over?” says Steve. “Are you rich now, Buck?”

“Tony pays pretty well, yeah,” says Bucky. “You’re rich too, you know.”

Steve blinks, trying to take this in. There are a million questions he wants to ask, starting with who Tony is, but then stops himself. There is a more pressing question at hand. 

“What do you mean I’m rich? I’m poor as shit, same as you. Or same as you were,” says Steve, confusedly. “Say, what year is it anyway?”

Natasha and Bucky exchange worried glances. 

“It’s 2026, Steve,” says Bucky, gently. 

The words ring in Steve’s ears. 

“What the fuck,” says Steve. “Not the fifties?” 

“Nope.”

“Oh, okay,” says Steve. He rubs at his head. He’s suddenly developed a splitting headache. “How is it — we should be dead,” he says, weakly. “It was  _ nineteen thirty-fucking-five _ , last I checked—”

“A lot’s happened.” 

“This is one of your stupid science fiction novels,” Steve shouts. “This is some H.G. Wells bullshit,” he says, slapping at his face. 

“What the hell are you doing?” Bucky yells, and runs over to Steve, grabbing Steve’s hands, holding them down. He’s so close, and he’s so big, and his hands are so solid against Steve’s arms— 

Steve feels a rush of arousal, and he looks down and blushes, hoping his sudden erection isn’t wildly visible in these tight jeans. 

“Steve,” says Bucky, in a more gentle tone. “Wouldya look at me?” 

Steve does, then, look up, stares at Bucky. Those gray eyes, those are the same, at least, even if his skin is rough and he has a beard that he  _ knows _ his Bucky couldn’t grow even if he wanted to, and his hair is as long as a woman’s. The skin around Bucky’s eyes wrinkles, as he smiles at Steve, helplessly. 

“This is real, pal,” he says, softly and slowly. “You’re in 2026, and so am I. Up until a few hours ago, you were a superhero named Captain America.”

Steve just laughs. 

“Captain America?” he says, weakly. “C’mon, Buck, that sound like some comic book shit.”

“It is, actually, comic book shit,” says Bucky, grimly. He finally lets Steve’s arms go, as if he’s convinced Steve will stop hitting himself. “They made comic books about you during the war,” he says. 

“What war?” says Steve, and he wants to laugh, this is so ridiculous. 

“The second world one,” says Bucky, and then he groans. “I know what this sounds like, this has got to sound so fucking weird,” he says, grinning at Steve tiredly. He rubs his cheek, a nervous tic Bucky has had since Steve knew him. A flash of gold glints off Bucky’s ring finger. 

“Married?” Steve squeaks. “You’re  _ married _ ?” 

A rush of despair takes him, one that he shakes his head to dispel. He always knew Bucky would get married. He always knew this day would come. But he always thought he would have a few years to run around with Bucky before he got hitched, taken away from Steve. But if he had just been unceremoniously booted into the future, he missed out on all those years, the years of freedom they were going to have. Missed out on maybe having Bucky for himself, the way he thought about late at night, when he fucked his fist and bit down on his wrist so his mother wouldn’t hear the noises he made through the too-thin walls of their apartment. 

“I am,” says Bucky, grinning. 

“He really is,” says Natasha, laughter in her voice. 

“To  _ who _ ?” says Steve, voice high with indignation. 

“Let’s, uh,” says Bucky, and looks back at Natasha. “Let’s get to that later, shall we?”

Steve thinks about fighting Bucky on that, and then realizes he’s got bigger problems to worry about. 

“Okay, so there was a second world war,” says Steve, shaking his head. “And I fought in it?”

“Did you ever,” says Bucky, seriously, looking at him proudly. “We both did.”

“Together?” asked Steve, suddenly kind of shy. 

“Yeah, Stevie,” says Bucky, and he’s smiling at Steve with an open, unguarded expression, the kind of look that Steve used to pray Bucky would grace him with, before. The kind of look that was saved only for Dottie, or Gretchen, or Phyllis. For girls. 

“How old are you, Steve?” asks Natasha, suddenly. “Need to figure out how much damage that wizard actually did, Dr. Strange wants to know.”

“Seventeen,” Steve tells her. “I turn eighteen in two months.” He chews his lip, thinking. “Bucky,” says Steve. “Where’s Ma? Did she make it to the next century, the way we did?”

There’s a pause. Natasha looks down, while Bucky just stares at him. 

“Oh,” says Steve, dully. 

“It’s not just her, Steve,” says Bucky. He sighs. “It’s everyone. Nearly everyone from our time is gone.”

“How did we get so lucky?” says Steve, bitterly. 

“I don’t know, pal,” says Bucky, sighing. 

“Can you send me back?” asks Steve, a pleading note entering his voice. “I think people need me back home, in Brooklyn. In my Brooklyn.”

Another hesitation.

“We’re not sure,” says Natasha, slowly, thoughtfully. “Methuselah cast a spell that de-aged you, but it wasn’t like when we de-aged Scott with the Pym Particles.”

“The what?” Steve demands. 

“So what was it like?” asks Bucky, ignoring Steve. 

“Like he cast the years off Steve,” says Natasha, turning to Steve. “Like he literally took your body and your mind back in time. This is the real seventeen year old Steven Grant Rogers, standing before us. Time moved through you, you haven’t moved through time.”

“So that means,” says Steve, mouth dry. “I can’t go back?”

“The spell will wear off, right?” asks Bucky. 

“Not sure,” says Natasha, studying a small rectangular square. “Dr. Strange says Methuselah’s magic is something he hasn’t seen before. It’s unknown to earth.”

“Is Methuselah a space alien?” says Steve, weakly. 

“Yes,” says Bucky. He turns back to Natasha. “So we need to find Methuselah,” he says. “Find him, force him to turn Steve back.”

“Back. Into. What.” says Steve, loudly. He considers smashing his coffee mug against the table if it will make him be heard. He decides against it, as attention has been turned back onto him. 

“Into this,” says Bucky, sighing. He takes his own rectangular square out of his pocket, presses it a few times, and shows Steve a picture of a much larger, much older version of himself, his arm around Bucky. Bucky is kissing his cheek. 

Steve points at the screen, in shock. He stares at Bucky, and wonders if his face is as white as it feels. 

“How,” whispers Steve.

* * *

Later, with Steve’s mind swimming with tales of a magic supersoldier serum, of being frozen for 70 years, of time travel, of saving the world a few times, Bucky ushers him to an examination room some stories below their apartment in Stark Tower. PAs and nurses poke and prod at Steve, taking more blood samples than Bucky is strictly comfortable with.

Tony Stark enters the room, this time free of the suit that scared Steve so much earlier. But he is wearing a white lab coat, notes Bucky, to his chagrin. 

“No,” says Bucky, crossing his arms and glowering. 

“What?” says Tony. “You don’t want Dr. Stark examining your hubby?” 

Steve turns towards Bucky, a question on his lips. Bucky doesn’t let him ask it. 

“I want a doctor,” says Bucky. “A  _ real _ one.”

“I know more than they do, besides, I sent these results over to Strange as well,” says Tony. He throws up some documents onto the screens. Steve is evidently distracted enough by the show of technology that he forgets to ask whatever uncomfortable question he was about to ask. 

“Well, Rogers,” says Tony. “You’re a very sick boy,”

“Tell me something else that’s new,” says Steve, darkly. “Is he just here to make fun of me?” he turns to ask Bucky.

“Medicine has improved a whole lot in the last century, bud,” says Bucky. “We’re going to get you treatment that we only could have dreamt of giving you in the ‘30s.”

“I don’t need all that,” says Steve, indignant. “I was doing fine before.”

“You nearly die when you’re 19 from influenza,” says Bucky, shortly. “We are not going through that again.”

Steve seems to deflate a little, but he stops fighting Bucky, finally, and turns to Tony. 

“Well, doc, what’s wrong with me,” he says, voice flat. He grits his teeth and Bucky feels bad for him. He knows how much Steve hates this: hates being cared for. 

“Scoliosis, for one. You’re a type 1 diabetic, you have high blood pressure, you are partially deaf, totally colorblind, and you’re asthmatic.” Tony stares at Steve. “Honestly, it’s a miracle you’re still alive.”

“Less editorializing, Tony,” Bucky growls. 

“Right, says Tony. “And you’re anemic. Did you have scarlet fever at some point? Was that a thing when you two were kids?”

“Yeah,” says Steve, shortly. “Had it when I was a baby.”

“So you developed rheumatic fever. That would explain the heart issues. I actually can’t believe you joined the army like this,” says Tony, whistling.

“Sorry, Barnes,” he says, turning to Bucky preemptively, before Bucky can curse at him, the way he wants to. “I’ll try to hold off the color commentary, but your boy here is sick with a capital ‘S’”. 

“Just give us the pills,” says Bucky, irritated. 

“Fine,” says Tony. “I’ve called in your prescriptions to the CVS across the street. There’s about seven things you’re going to take everyday, plus various inhalers for the asthma. And then tomorrow we’ll get you fitted for a hearing aid and glasses.”

“How did you call in the prescriptions?” asks Bucky. “You’re not an MD.”

“I stole Banner’s pad this morning,” says Tony, looking inordinately proud of himself. 

“That’s probably a felony,” says Bucky, sighing. “You good, Stevie?”

“Yeah,” says Steve, sliding off the examination table, resolutely not looking at Tony. Bucky’s heart kind of sinks at that — he knows how much his Steve gets along with Tony Stark, and he doesn’t want to find out what else is different about this Steve Rogers. 

“How’s the arm, Barnes?” asks Tony. “I wanted to talk to you about the upgrades Shuri emailed me yesterday.”

“Later,” says Bucky, irritated that Steve overheard. “Let’s go to the pharmacy, Steve,”

They’re in the elevator before Steve turns to Bucky to pepper him with questions. The first one is wholly expected. 

“What’s with your arm, Bucky?” says Steve, eyes wide. “What did he mean, by upgrading it?”

Bucky sighs. Now or never, he supposes. He takes his glove off, lets a shocked Steve examine his metal hand. 

“Lost it in the war,” says Bucky. He’s well aware that he’s only told Steve the story of what happened to Steve, how Steve landed in the 21st century. That’s by design. He doesn’t necessarily want to tell him more about how Bucky landed in 2026. That’s a sadder story. “A kid not too much older than you made me this for me,” he says, pulling up his sleeve so Steve can see more of Bucky’s metal arm. 

“Jesus Christ, Bucky,” says Steve, breathless. “You lost your fucking arm?” he asks, voice laced with heartbreak. 

“It’s a long story,” says Bucky, gruffly. “Fell off a train.” Steve’s sympathy, for some reason, isn’t that hard to take. Anyone else’s care would be. But not Steve’s. 

“Everyone thinks it’s so cool, you know?” says Bucky, softly. “I’m like, a cyborg now. I have this metal arm that can do cool things, that can take shots, that can lift like a motherfucker. But I’d give it up in a heartbeat for my real arm back,” he says, grinning sadly. 

“Oh Bucky,” says Steve, and he hugs Bucky around Bucky’s midsection, as hard as his little arms can manage. Bucky wraps his arm, his flesh-and-blood one, around Steve’s skinny shoulders, and squeezes. Steve looks up at Bucky and smiles, blinking away tears, and Bucky feels his heart grow about three times, and wonders if now is a good time to tell Steve what they are to each other in 2026, what they’ve learned how to be. 

But then the elevator doors open, and there’s a crowd of people waiting to stream in, so Steve and Bucky separate.

“Here’s another question,” says Steve, shouting over the din of the first floor of Stark Plaza. “Why was that doctor such a prick?”

* * *

They get their prescriptions, buy a few more outfits for Steve, and head back to the tower. By this point, Steve is yawning and Bucky feels a little tired too, 

“Maybe I should introduce you to movies in the 21st century,” says Bucky. 

“I mean, I’ve seen a movie before.” says Steve. 

“Not like this,” says Bucky, grinning. They settle onto the couch, and Bucky rifles through his blu-ray collection. He finally picks out what he’s looking for, and loads it into the DVD player. 

The familiar crawl script starts playing on the screen, and Bucky has to pause to read the script out loud — Steve can’t get his eyes to focus on it. 

“It is a period of civil war. Rebel spaceships, striking from a hidden base, have won their first victory against the evil Galactic Empire,” reads Bucky, while Steve laughs at the voices Bucky makes.

“It’s a pretty old movie, actually, released over forty years ago,” says Bucky, eagerly, as the gigantic spaceship appears on the screen.

“This was forty years ago?” says Steve.

“Yeah, movie making has evolved since this,” says Bucky. “They still used puppets and stuff to do the aliens. Now it’s all CGI.”

“Bucky, I’m still stuck on the fact that it’s in color,” says Steve, laughing. 

They watch and watch and Steve gets tired. At some point, he stretches out and yawns, curls up into Bucky’s side, closes his eyes. Bucky tucks his real arm around Steve, heart in his throat, not sure if he’s doing the right thing.

Bucky isn’t sure where they stand, honestly. This, this  _ closeness _ , it doesn’t happen for a few more years in Bucky’s timeline — Steve only kisses Bucky when they’re both 21. According to what Steve told Bucky, Steve’s always carried a torch for Bucky, since they met on the playground in 1924, which means that  _ this _ Steve, the one currently curled up against Bucky’s side, must also be violently in love with Bucky. 

But does that mean that this Steve likes  _ this _ Bucky? Grizzled, older, seen-too-much Bucky, this version of Bucky who could break this Steve’s fragile body like a twig? Yes, older Steve loves older Bucky — otherwise, why would he have married him? Bucky’s not insecure enough to doubt the love of his own husband. But this Steve, this child in his arms — he loves the boy Bucky was, the lean, lithe player, the lothario who always had a girl in his arms (for appearances’ sake), the one with the cocked hat and the ready smile on his lips. 

That man — that  _ boy _ , that  _ child _ — is nearly a hundred years removed from who Bucky turned out to be. 

Bucky is saved from further musing by the roll of the end credits. He grabs the remote, turns the television off, and gently starts shaking Steve awake. 

“No,” says Steve, who is fully pressed up against Bucky’s chest. 

“Yeah, kid,” says Bucky, grinning despite himself at Steve’s recalcitrance. “It’s time to get up, have some dinner,”

Steve opens an eye, and then another one, and sits up, when he realizes where he is. “Shit, how long was I out?” he asks. 

“Since we left Tatooine,” says Bucky. 

“Huh?”

“Never mind,” says Bucky, grinning. Maybe  _ Empire Strikes Back  _ will be more to Steve’s liking. 

They eat reheated pizza, which Steve approves of. Bucky makes a big salad — now that he knows about the scientific connection between good nutrition and good health, he’s going to be force feeding Steve as many raw leafy greens as possible. Bucky tries to not watch Steve eat, tries to not to worry when Steve stops at one slice and one bowl of salad. He shakes his head. His Steve ate like a racehorse, but Steve without the serum; he always ate like a bird. 

Around eleven, Bucky tells Steve he’s turning in. 

“Don’t you have to go home, Bucky?” asks Steve. 

“Home where?” asks Bucky, surprised. 

“To your wife,” says Steve, smiling at Bucky. The smile looks a little forced. 

“She’s out of town,” says Bucky, hating himself a little for lying. 

“Oh,” says Steve, looking down. “Sad I missed the wedding!” he says with put-upon cheer, not quite meeting Bucky’s eyes. 

Bucky, who purposely hid all wedding pictures in their apartment when Steve was passed out earlier, says nothing.

Steve takes the main bedroom — the one that Bucky and Steve used to share. 

Bucky installs himself in the guest bedroom. As he’s falling asleep, he sends a text to the Avengers group chat: 

> Guys, do me a favor and don’t tell Steve that we’re married? I’m trying to ease him into the 21st century, don’t want to shock him unnecessarily.

He waits until he gets assents from his teammates before trying to fall asleep. 

**Author's Note:**

> Hope you liked it! Remember to comment, it keeps me alive (and ensures that there will be more chapters!)


End file.
